Projective Ore-Degree Conditions for Intersection Theorems in Vector Spaces
Combinatorics
2026-07-28 v1
Abstract
Let be an -dimensional vector space over the finite field , and let . The \emph{projective Ore-degree} of is the minimum, over all -subspaces , of the sum of the -degrees of the projective points contained in . We prove sharp projective Ore analogues of the vector-space Erd\H{o}s--Ko--Rado and Hilton--Milner theorems. The Ore--Erd\H{o}s--Ko--Rado theorem holds for , with equality only for a full point-star. For nontrivial intersecting families, we determine the sharp Ore--Hilton--Milner threshold, together with the complete equality classification, when and , or when and . We further determine a sharp projective Ore-degree threshold forcing a direct-sum matching of size when and , and derive a multicolour Ramsey consequence.
Cite
@article{arxiv.2607.25598,
title = {Projective Ore-Degree Conditions for Intersection Theorems in Vector Spaces},
author = {Mengyu Cao and Mei Lu and Xuyang Yan and Haixiang Zhang},
journal= {arXiv preprint arXiv:2607.25598},
year = {2026}
}